Current military bayonets designed with the M4 Carbine/M16 platform are limited as to the weapons that can be mounted to the outside of the platform. Mounts for these bayonets usually consist of a lug that is fixed to the barrel of the firearm. The lug protrudes down from barrel where it combines with the muzzle ring of the bayonet. The muzzle ring slides over the muzzle and allows the lug to fix the bayonet in place. This design limits the mounting of current bayonets to weapons that have a sufficient length of exposed barrel to accommodate the length of the handle on the bayonet and that have the barrel circumference to accommodate the muzzle ring. What is needed is an adaptor that overcomes these drawbacks.